Conventional data transmission systems and telephone systems, such as land line telephone systems, radio telephone systems and mobile telephone systems, become faster in their data transmission properties all the time. Different systems and devices which enable for instance the introduction of new services become available at quite a fast rate. The introduction of services is, however, slowed down by the fact that the data transmission rate between a service provider and user is relatively slow. In addition, at least some systems require complex control and base station equipment to function, and their construction is economically a very expensive investment.
Data transmission can be relatively fast in one section of the system, but it can be said that the data transfer rate between a base station and terminal equipment, for instance, is still relatively low. It can also be noted that it is today not yet possible to transfer quickly enough as much data to the terminal equipment as required to provide the user as extensively as possible with different services which function sufficiently quickly from the user's point of view.
Publication U.S. Pat. No. 5,613,190, for instance, discloses a system which is made up of service providers, a broadband data transmission link, a distribution point in the customer's premises and user terminals. The data to be transmitted is broadband information from the service provider to the customer. Signal distribution at subscriber end takes place through an air interface between a transponder and a second transponder in the terminal. The terminals are assumed to be fixedly installed. In the premises of the subscriber to the service, there is a transponder which transforms received broadband information to an RF signal to be transmitted to the air interface. The transponder can be connected to a broadband network employing ADSL technology, for instance, in which case the RF air interface is between two complete ADSL modems. The ADSL technology used in the publication provides a transfer rate of 1.5 Mbit/s in the downlink direction.
Publication U.S. Pat. 6,021,158 discloses a data transmission system which comprises a micro wave link connected to a broadband network, through which bi-directional broadband data is transmitted by the point-to-multipoint principle to points from which it is distributed by twisted-pair copper cables to the customers. The data transmission system comprises DSL modems. The publication relates to the selection and allocation of the frequency band for the wireless section on the basis of the channel capacity and signal quality.
Publication WO 00/04475 discloses a method of processing e-commerce data, and publication WO 00/04476 discloses an e-commerce telephone. DSL technology can be utilized in the solutions disclosed in the publications.